[Update 12/16/2011]
ExxonMobil's own chart shows 75% of today's oil was discovered before 1980.
Via WashPost: Oil’s getting harder and harder to come by
First check the Oil Drum for what Peak Oil is not: Five Misconceptions About Peak Oil
That puts in context the analysis at Early Warning that Saudi oil production has been declining for the past few months despite more rigs coming online: Saudi Oil Production Declining (also interesting that Saudi Arabia could not meet their promised increase in output earlier this year)
